REVIEW #22
A PRACTICE PRACTICAL EXERCISE
There are 3 parts to this exercise. PART 1 contains questions about 10 slides. PART 2 is based a schematic brain drawing; you are asked to draw in a pathway and supply some short answers. PART 3 deals with a clinical problem. Among other things you are asked to pick the probable lesion, choosing from the four choices provided.
REVIEW 22, Part 1
QUESTION 1
1) Name this nucleus.
2) The arrow points to a small opening connecting two large spaces. Name the small opening.
3) Describe the cortical region that contributes axons to the pathway that descends through this part of the internal capsule
ANSWER 1
1) Name this nucleus. The Caudate Nucleus.
2) The arrow points to a small opening connecting two large spaces. Name the small opening. The Interventricular Foramen (of Monro) .
3) Describe the cortical region that contributes axons to the pathway that descends through this part of the internal capsule. The pathway is the Corticospinal Pathway or Pyramidal Tract. We tend to think of this important motor pathway as originating in the in the motor cortex of the precentral gyrus, but actually a significant number of the axons have their axons in the postcentral region of the parietal lobe.
QUESTION 2
1) Name this sulcus.
2) Name this small "bump" on the dorsal surface of the brainstem.
3) Neurons with their cell bodies in this region send axons to terminate in what structure?
ANSWER 2
1) Name this sulcus. The Calcarine Sulcus.
2) Name this small "bump" on the dorsal surface of the brainstem. The Inferior Colliculus.
3) Neurons with their cell bodies in this region send axons to terminate in what structure? The Cerebellum.
QUESTION 3
1) Name this nucleus.
2) Suppose this nucleus were destroyed on the right side. Give 2 abnormalities observed when you tested the motor function of the corresponding cranial nerve.
3) Give 2 types of sensory information conveyed by the axons in this tract.
ANSWER 3
1) Name this nucleus. The Inferior Vestibular Nucleus.
2) Suppose this nucleus were destroyed on the right side. Give 2 abnormalities observed when you tested the motor function of the corresponding cranial nerve. This is the Hypoglossal Nucleus. If you asked the patient to extend the tongue, it would deviate to the right; the muscles on the right would be atrophied, and muscle fasciculations might be apparent.
3) Give 2 types of sensory information conveyed by the axons in this tract. This is the tractus solitarius. The rostral part of the tract contains fibers conveying the sense of taste. The caudal part of the tract contains fibers conveying (non-pain) sensory fibers from the viscera; these fibers form the afferent side of reflexes that control heart rate, gut motility, etc.
QUESTION 4
1) Where are the neuron cell bodies that contribute axons to the medial (shaded) part of this pathway?
2) What cranial nerve provides the major input to this sensory nucleus?
3) Where will most of these decussating fibers terminate?
ANSWER 4
1) Where are the neuron cell bodies that contribute axons to the medial (shaded) part of this pathway? This is the medial part of the Medial Lemniscus. The fibers running in this region have their cell bodies in the contralateral Nucleus Cuneatus.
2) What cranial nerve provides the major input to this sensory nucleus? The Trigeminal Nerve (see atlas figure).
3) Where will most of these decussating fibers terminate? This is the Trapezoid Body, part of the ascending auditory pathway. Most of the fibers will terminate in the Inferior Colliculus, but some will synapse in intermediate nuclei along the way.
QUESTION 5
1) What deficit in eye movement would result if this pathway were cut on the left side of the brainstem?
2) Where will this smsll compact bundle of axons terminate? (Hint: it is NOT a somatic sensory pathway)
3) Name one structure that has contributed axons to this decussating pathway. (be specific).
ANSWER 5
1) What deficit in eye movement would result if this pathway were cut on the left side of the brainstem? The resulting condition is termed Internuclear Ophthalmoplegia. Vertical eye movements, and conjugate eye movements to the left would be normal. When conjugate eye movement to the right is attempted, the right eye would turn laterally, but the left eye would stop at mid position and not turn further to the right.
2) Where will this smsll compact bundle of axons terminate? (Hint: it is NOT a somatic sensory pathway) The pathway is the Brachium of the Inferior Colliculus. Fibers within it will terminate in the Medial Geniculate Nucleus.
3) Name one structure that has contributed axons to this decussating pathway. (be specific) The Dentate, Globose and Emboloform Nuclei (all deep nuclei of the Cerebellum) all contribute ascending fibers to thei decussation.
QUESTION 6
1) Cutting this pathway might alter what reflex?
2) Describe the loss in sensory function that would result if tis nucleus were completely destroyed on the right side.
3) At what level will the fibers descending in this pathway (between the dashed lines) decussate?
ANSWER 6
1) Cutting this pathway might alter what reflex? NONE! This is the Posterior Commisure. It's true that it contains fiber traveling from each lateral geniculate nucleus to the contralateral Edinger-Westphal Nucleus and that this pathway may participate in the Consensual Pupillary Light Reflex. But the partial crossing of visual fibers in the Optic Chiasm provides an alternate route from each eye to both Edinger-Westphal Nuclei.
2) Describe the loss in sensory function that would result if tis nucleus were completely destroyed on the right side. The result would be a left homonymous hemianopia.
3) At what level will the fibers descending in this pathway (between the dashed lines) decussate? The pathway is the Corticospinal pathway or Pyramidal Tract. The decussation occurs in the region of transition between the caudal Medulla and the upper cervical cord (C1).
QUESTION 7
1) What cortical region provides an input to this nucleus? (include the word ipsilateral or contralateral in your answer)
2) Name this region.
3) Name this small "C" shaped structure.
ANSWER 7
1) What cortical region provides an input to this nucleus? (include the word ipsilateral or contralateral in your answer) The ipsilateral Pre-central Gyrus.
2) Name this region. This is the Substantia Nigra.
3) Name this small "C" shaped structure. It is the Dentate Gyrus, a component of the Hippocampal Formation
QUESTION 8
1) Name one pathway that provides an input to this nucleus.
2) Where will most of the fibers in this structure terminate?
3) Name this nerve.
ANSWER 8
1) Name one pathway that provides an input to this nucleus. The ventral secondary trigeminal tract. The Ventral Secondary Trigeminal Tract.
2) Where will most of the fibers in this structure terminate? The Lateral Geniculate Nucleus.
3) Name this nerve. The Oculomotor Nerve.
QUESTION 9
1) Name this gyrus.
2) Name this nucleus.
3)Name this space.
ANSWER 9
1) Name this gyrus. The Cingulate Gyrus.
2) Name this nucleus. The Putamen.
3)Name this space. The Inferior Horn of the Lateral Ventricla.
QUESTION 10
1) Where will most of these fibers terminate? (give only one structure)
2) Name this pathway.
3) Give one output pathway that originates in this nucleus.
ANSWER 10
1) Where will most of these fibers terminate? (give only one structure) In the Mammillary Body.
2) Name this pathway. The mammillothalamic Tract.
3) Give one output pathway that originates in this nucleus. The Stria Terminalis or the Ventral Amygdalofugal Pathway.
PART 2
Draw in a pathway and supply some short answers.
PART 3
This page describes aa clinical problem.
Scroll down to the next page for the potential lesions
PART 3
This page describes aa clinical problem,
PART 3
This page provides answers;
